The present invention relates generally to the construction of airplane runway, and more particularly to processes of finishing slits of surface layers of runway, taxiway, apron, hangar, and the like.
The conventional process of finishing slits of surface layers of the runway and the like is described and discussed hereinafter with reference to the accompanying FIGS. 1-20. The runway in question has a length of 3000 meters, a width of 60 meters, and a thickness of 30 centimeters.
As shown in FIG. 1, the runway is formed of a gradation layer A, and a surface layer 10 which is paved on the gradation layer A and is formed of pavement concrete (PC) or reinforced concrete (RC).
As shown in FIG. 2, the runway is provided on the gradation layer A with a plurality of first surface layer units 10A, which are parallel to one another at an interval of six meters and are equal in length to the runway. The surface layer units 10A are formed of pavement concrete or reinforced concrete.
As shown in FIG. 3, the runway surface layer 10 is further formed of a plurality of second surface layer units 10B, which are paved side by side with the first surface layer units 10A such that a second slit 17 is formed in the juncture of the first surface layer unit 10A and the second surface layer unit 10B.
As shown in FIG. 4, the surface layer 10 is provided with a longitudinally-oriected expansion slit 11, which is formed by cutting in the juncture of the first surface layer unit 10A and the second surface layer unit 10B. The expansion slit 11 has a depth of 3 cm, and a width of 1 cm.
As shown in FIG. 5A, the runway surface layer 10 is provided with hundreds of guide slits 12, which are arranged at a predetermined interval such that they are perpendicular to the length of the runway, The guide slits 12 are intended to prevent the formation of irregular cracks in the surface layer 10.
As shown in FIG. 5B, each of the guide slits 12 is provided with a horizontally-oriented expansion slit 13 which has a depth of 3 cm and a width of 1 cm, thereby resultion in formation of a number of checkers 14 on the surface layer 10, as shown in FIG. 6. The checkers 14 are intended to prevent the surface layer 10 from being damaged by the effects of expansion and contraction of the surface layer 10 due to the climatic factors.
As shown in FIGS. 7 and 8, the longitudinal expansion slit 11 and the horizontal expansion slit 13 are provided with a polyethylene (PE) strip 15 and a polyurethane (PU) slit-filling agent 16 covering the PE strip 15. The construction of the surface layer 10 is thus completed such that the runway is resistant to water.
The conventional process described above is also used to build taxiway, apron, hangar, and the like, The conventional process has several deficiencies, which are explicitly described hereinafter.
In light of the first surface layer units 10A and the second surface layer units 10B being constructed separately, there is formation of the second slit 17 in the juncture of the first surface layer unit 10A and the second surface layer unit 10B, as shown in FIGS. 3, 4, and 7. Upon completion of the guide slit 12, a through slit 18 is formed in such a way that it extends from the bottom of the guide slit 12 toward the gradation layer A, as shown in FIGS, 5A, 5B, and 8. The slit-filling agent 16 is coated on the inner walls of the longitudinal expansion slit 11 and the horizontal expansion slit 13, without penetration into the small holes of the inner walls of the expansion slits 11 and 13. As a result, the slit-filling agent 16 is apt to be stripped form the expansion slits 11 and 13 under the influence of the climatic changes, The slit-filling agent 16 is different in heat expansion coefficient from the first surface layer unit 10A, the second surface layer unit 10B, the pavement concrete, and the reinforced concrete. As a result, a water interstice 11xe2x80x2 is formed between the longitudinal expansion slit 11 and the slit-filling agent 16, as shown in FIG. 9. Similarly, a water interstice 13xe2x80x2 is formed between the horizontal expansion slit 13 and the slit-filling agent 16, as shown is FIG. 10. The water finds its way into the gradation layer A via the water interstice 11xe2x80x2 and the second slit 17, as shown in FIGS. 7 and 9. Similarly, the water finds its way into the gradation layer A via the water insterstice 13xe2x80x2, the guide slit 12 and the through slit 18, as shown in FIGS. 8 and 10. In light of the effect of the water erosion, A void A1 is formed in the gradation layer A, as shown in FIG. 11. The void A1 weakens the structural strength of the area in the vicinity of the longitudinal expansion slit 11. Such a weakened area of the surface layer 10 of the runway is apt to cave in when the surface layer 10 is exerted on by an external force of an airplane or heavy equipment, thereby resulting in formation of a pothole 19 in the surface layer 10 of the runway, as shown in FIG. 11. It is conceivably unsafe for an airplane to land or take off on a runway having potholes. The only workably remedy to provide the gradation layer A of the runway with protection against the water erosion is to replace the slit-filling agent 16 periodically. The periodic replacement of the slit-filling agent 16 is not cost-effective and is apt to hinder the normal operation of the airport.
The rain water tends to accumulate in those checkers 14 which are located in the juncture of the longitudinal expansion slit 11 and the horizontal expansion slit 13. As a result, the checkers 14 are susceptible to surface crack 14xe2x80x2, as shown in FIG. 12. The surface crack 14xe2x80x2 will eventually become a pothole 19, The conventional method of repairing the surface crack 14xe2x80x2 involves a first step in which two slender slits 141 are formed by cutting along two longitudinal sides of the surface crack 14xe2x80x2, as shown in FIG. 13. Thereafter, the surface layer 10 located between the two slender slits 141 is removed to form a shallow trench 142 which has a width of 30 cm and a depth of 10 cm, as shown in FIG. 14. As shown in FIG. 15, the shallow trench 142 is then filled with a filling material 20, which is a mixture containing water, epoxy resin quartz sand, pavement concrete, or reinforced concrete, The filling material 20 is different in heat expansion coefficient from the surface layer 10 and is therefore vulnerable to being separated from the side walls and the bottom wall of the shallow trench 142, thereby resulting in formation of a second process silt 21 between the filling material 20 and the shallow trench 142, as shown in FIG. 16. The water W enters from the second process slit 21 into the surface crack 14xe2x80x2 which is located under the shallow trench 142. Subsequently, the water W enters the gradation layer A from the surface crack 14xe2x80x2. It is also likely that a gap 23 is formed between the bottom wall of the shallow trench 142 and the filling material 20, as shown in FIG. 17. This is due to the fact that the filling material 20 is exerted on by the expansion forces of the side walls of the shallow trench 142. As a result, the filling material 20 is partially jutted out of the shallow trench 142. The surface layer 10 of the runway is therefore rugged, In other words, the filling material 20 might become a culprit responsible for the flat tire.
In the event that the surface crack 14xe2x80x2 is numerous, the surface layer 10 of the runway is replaced with a new surface layer. The process of paving a new surface layer involves a first step in which a thickness of 10 cm of the surface layer 10 is removed from the runway, so as to form an intermediate layer 10xe2x80x2, as shown in FIG. 18. The intermediate layer 10xe2x80x2 is sprayed with a layer of asphalt, thereby resulting in formation of a holding layer 101 on the intermediate layer 10xe2x80x2. The holding layer 101 is then paved with asphalt cement 30 having a thickness of about 5 cm. The asphalt cement layer 30 is covered with a pavement reinforcing fabric 40, which is made of polyacrylic fiber or polyester fiber. Finally, the pavement reinforcing fabric 40 is covered with an asphalt concrete layer 30, which has a thickness of 5 cm. A new runway surface layer 30xe2x80x2 is thus completed, as shown in FIG. 19.
The primary objective of the present invention is to provide a process for finishing slits of the surface layer of an airplane runway in such a manner that the gradation layer of the airplane runway is immune from the water erosion, thereby prolonging the service life span of the airplane runway.
The process of the present invention is intended to overcome the deficiencies of the conventional processes described above. According to the process of the present invention, various slits of the surface layer of a runway are effectively resistant to water so as to minimize the water erosion of the gradation layer of the runway. The process of the present invention involves a first step in which the slits of the surface layer of the runway are properly heated to open up the capillary holes of the silts, so as to enhance the bonding of the asphalt synthetic agent with the side walls of the slits. As a result, various slits of the surface layer of the runway are effectively sealed off to an extent that the water is prevented from permeating into the gradation layer of the runway. The slits of the surface layer are further provided with a soft interface capable of preventing the formation of the second process slit, the surface crack, and the reflective crack.
The soft interface of the present invention is securely attached to the slits such that the chemical properties of the soft interface are not affected by the climatic changes, and that the soft interface is capable of converting a vertical internal stress into a horizontal action force, thereby preventing the formation of the reflective crack in the surface layer of the runway.
The process of the present invention involves the use of waterproof rubber cloth by which all slits of the surface layer of the runway are made waterproof. As a result, the gradation layer of the runway is free of voids which are caused by the water erosion. The use of the waterproof rubber cloth can also prevent the formation of the reflective crack in the surface layer of the runway. The process of the present invention eliminates the formation of potholes in the surface layer of the runway.